The present invention is related to direct aiming of the muzzle of a moving or stationary direct fire weapon. Through the use of modern electrooptical technology, the gunner is presented a stabilized image of the target along with a referencing reticle enabling the direct aiming of the muzzle with respect to the target.
Conventional techniques of weapon aiming dictate that to maximize gun system repeatability, the axis of the muzzle should be placed on the desired gun-to-target line. The muzzle axis is defined by the foremost length of the gun tube equal to four times the diameter of the gun tube. Current sighting and aiming systems in large caliber direct fire weapons such as tanks do not directly point the muzzle of the gun. These systems employ sighting and aiming techniques that point the axis of the breech end of the gun on the desired gun-to-target line. These modern systems employ optical sights such as telescopes and periscopes which are mounted either to the mantlet or the turret of the tank and are linked to the pointing axis of the gun breech by by mechanical, optical or servo-mechanical stabilization means. The orientation of the muzzle axis is derived by either system zeroing techniques or muzzle referencing techniques. In either case, there is no direct means of pointing the muzzle at the target during an engagement. The gunner must use an eyepiece which is mounted to the tank structure. The gunner must keep his eye aligned with the eyepiece in order to minimize parallax in the sighting system. Current systems offer a minimal solution to the eye alignment problem by providing a brow pad to stabilize the gunner's head.
In addition to the basic sighting system, superelevation of the gun tube is introduced to the system through fire control computers based on either the measured or estimated range to the target. This technique "softens" the connection between the sight alignment and the breech axis alignment in elevation. Systems with stabilization further "soften" the sight/gun connection due to separate stabilization of the sight and gun. The stabilization system maintains the gun's breech axis in a position that is coparallel to the pointing direction determined by the gunner while the tank is moving. No direct means is provided in stabilization systems to control the muzzle pointing direction.
Recent sighting systems also employ muzzle reference devices, either active or passive, mounted on the muzzle of the gun to measure the difference between the pointing direction of the muzzle and the pointing direction of the breech. As currently used, the systems provide data to adjust the relative position of the sight axis with respect to the breech axis in order to maintain system zero. These muzzle reference devices can be made to operate in either a continuous or intermittent mode depending on the specific system design. It should be pointed out that these systems do not directly reference the muzzle direction to the target. Controlling the breech direction in order to stabilize the muzzle motion on a moving tank would require servo systems capable of delivering two to four times the power Presently available in tank stabilization systems.
The most recent development in sighting systems is the Precision Aim Technique (PAT) which provides an appropriate firing time, causing the projectile to exit the muzzle of the gun when the muzzle is within a predetermined position window with respect to the breech. Essentially, this system causes repeated firings from a moving gun tube to occur when the muzzle is in the same position with respect to the breech. The PAT significantly enchaces shot to shot repeatability without adding any burden to the fire control and stabilization systems. Although the PAT system significantly reduces dispersion of shot about the center of impact for rounds fired from a moving gun tube, it does not directly adjust the center of impact and the aim point.